Organic EL device has many advantages such as self-emitting, wider viewing angles, faster response speeds and highly luminescence. Their simpler fabrication and capable of giving clear display comparable with LCD, making organic EL device an industry display of choice. Organic EL device contain emitting materials which are arranged between a cathode and a anode, when a applied driving voltage is added, an electron and a hole were injected into the emitting layer and recombined to form an exciton. The exciton which results from an electron and a hole recombination have a singlet spin state or triplet spin state. Luminescence from a singlet spin state emits fluorescence and luminescence from triplet spin state emits phosphorescence.
Organic EL device are generally composed of functionally divided organic multi-layers, e.g., hole injection layer (HIL), hole transporting layer (HTL), emitting layer (EML), electron transporting layer (ETL) and electron injection layer (EIL) and so on. A emitting material have good charge carrier mobility and excellent operational durability can lower driving voltage and power consumption, increasing efficiency and half-life time of organic EL device.
For full-colored flat panel displays in AMOLED, the compound used for the blue emitting layer are still unsatisfactory in half-life time and efficiency. Many compounds are used for fluorescent blue host in emitting layer. U.S. Pat. No. 5,935,721 used 9,10-di(naphthalen-2-yl)anthracene (AND) as blue host in emitting layer. U.S. Pat. No. 7,691,492 used 1,1-(9,9-dimethyl-9H-fluorene-2,7-diyl)dipyrene (DFDP) as host for blue organic EL device. These compounds still have disadvantages for industrial practice use.
In the prior invention U.S. Pat. No. 9,048,437B2, Yen et al. employ an indenotriphenylene skeleton link to a heteroaryl group substituted naphthyl anthracene group to finish the fluorescent blue emitting compounds. In the present invention, for the purpose to prolong the half-life time and improve efficiency for fluorescent blue emitting organic EL device we employ an indenotriphenylene skeleton link to a fused ring hydrocarbon units with two to four rings substituted phenyl anthracene group can display higher half-life time and efficiency than the prior invention.